Add a domain that you already use for on-premises services

Say your organization name is Fourth Coffee and your domain looks like this: fourthcoffee.com. After you add your domain and verify in Office 365 that you own it, you can set up Office 365 email addresses like alan@fourthcoffee.com and a website like www.fourthcoffee.com.

If you want to set up a hybrid email scenario with your domain, it’s easier to do if you have the same domain name for your on-premises email and your Office 365 email. Why set up a hybrid deployment? It lets you, for example, have a shared address book and shared free/busy calendar information as well as route email between your on-premises Exchange Server and email on Office 365.

Here are a few things to keep in mind about adding your on-premises domain to Office 365:

When you add and verify your domain in Office 365, it doesn’t affect your current on-premises services. It just means that the domain is ready to set up with Office 365 email and other cloud services when you’re ready to do that. Email will continue to arrive at your current on-premises email server if that’s what you’ve got set up already.

If you’re setting up more-complex scenarios like single sign-on or a hybrid setup with Exchange on-premises, you do that after you add and verify your domain. We’ll walk you through the steps.

After you add your domain to Office 365, you can change your Office 365 public website to use your own domain name, like fourthcoffee.com. You’ll want to customize the site first so that it has all the right information and links for people who want to learn about your organization.

When you just add and verify your domain in Office 365, there is no impact to users.

When you set up your services with your domain, unless you’re using a hybrid Exchange deployment, you want to be sure that everyone who gets email by using your domain name also has an account in Office 365.

To use your existing domain in Office 365, you type your domain name and verify in Office 365 that you own it. Adding the domain name makes it available to use with email addresses and other services as you set them up. Adding the domain doesn’t have any impact on your email or other services.

If you’re comfortable with what’s involved in using your domain with Office 365, you’re ready to get started.

We provided step-by-step instructions for verifying domain ownership with many domain registrars, but you might still prefer to have help adding a domain to Office 365. You can find a list of partners in the Office 365 Marketplace.

Keep using your initial onmicrosoft.com domain with Office 365

If you want to keep using the initial onmicrosoft.com domain that you chose when you signed up for Office 365, you can do that instead of adding your custom domain. Read more about the initial .onmicrosoft.com domain.